Head Mods & Rebuild

Posted Jan 14, 2016 Updated Feb 25, 2026

By Turbo Camaro

1 min read

Turbo Camaro’s head and valve train pre-rebuild

Semi-dismantled Chevy 250 head

As mentioned all over the internet, if you had to focus your attention on one part of the Chevy inline 6 to gain power, it would be the cylinder head. The head was cast for stability and economy and requires significant modification and upgrades to get decent performance gains.

The following is a list of things you can do to improve the Chevy 250 head for power:

Install a lump port kit
Increase valve size to 1.94/1.6 valves
Complete a full intake and exhaust port job

[Image showing a cross-section of a Chevy inline-6 head with a lump kit installed in the intake port]

Hi-Flow lump kit for Chevy inline 6’s

Completing the above requires the head to be completely disassembled. Once disassembled, you’ll want to lap the valves and prep the head for assembly.

When the lump kit was installed in Turbo Camaro, it was filmed and uploaded below.

Valves are waiting to be cleaned and lapped

Valve stems pushed through a pizza box

With the ports opened and the lumps installed, it’s time to lap the valves. Combustion chamber efficiency and overall compression will be affected by how well the valves are lapped.

Since Turbo Camaro received a performance camshaft, new valve springs were also required. A set of performance springs and retainers were picked up from 12bolt.com. The new springs handle up to .530 lift.

Head ported, lumped and painted. Valve job complete.

In the Summer of 2017, the head was pulled and professionally machined for larger 1.84” intake and 1.6” valves. The guides were also cut to allow for positive valve seals instead of stock o-rings.